Effect of a trace of water vapor on Ohmic contact formation for AlGaN/GaN epitaxial wafers

✍ Scribed by W.S. Lau; W.T. Wong; Joy B.H. Tan; B.P. Singh

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 208 KB
• Volume: 48
• Category: Article
• ISSN: 0026-2714
• DOI: 10.1016/j.microrel.2008.01.006

✦ Synopsis

The authors observed that a trace of water vapour can have a significant degradation effect on Ohmic contact formation for AlGaN/ GaN high electron mobility transistors (HEMTs). The degradation effect due to a trace of water vapour is less serious for n-GaN. This is a more serious problem for AlGaN/GaN HEMT than AlGaAs/GaAs HEMT or InP based HEMT because of the higher temperature needed for Ohmic contact annealing when AlGaN or GaN are involved. Using cooling water with a temperature slightly higher than the ambient temperature during rapid thermal annealing (RTA) appears to be the best approach.